Time-frequency based robust OFDM channel equalization

Orthogonal Frequency Division Multiplexing (OFDM) has become the standard method in the next generation mobile communication systems because of its advantages over single carrier modulation schemes on harsh channel environments. However, inter-carrier interference due to Doppler frequency shifts, and multi-path fading severely degrades the performance of OFDM systems. Estimation of channel parameters is required to use coherent receivers. In this paper, we present a computationally efficient, time-frequency (TF) based channel estimation method for OFDM channels whose frequency response may be changing over a single transmit symbol. The Discrete Evolutionary Transform is used to obtain a complete model of a multi-path, fading and frequency selective channel. A TF receiver is designed to detect the sent data by using estimated channel parameters. Performance of the proposed method is tested on different levels of channel noise, and Doppler frequency shifts.